Comparison Between Child Cadavers and Child Dummy by Using Child Restraint Systems in Simulated Collisions 760815

At present, numerous restraint systems for children applied in vehicles are in general considered for the use on the back seats. Up to now, only impact tests with dummies and animals have been carried through by these systems. Out of the great number of children seats and belts we used a system (deformable safety impact table combined with a lap-belt) which has been investigated by us during frontal impacts utilizing two dummies and four cadavers of children in the age of 2,5 up to 11 years having body weights of 16 up to 31 kg. The tests have been conducted on the deceleration-sled track at the Institute of Legal Medicine of the University Heidelberg. Impact velocities of 30 km/h and 40 km/h at a medium deceleration of 20g have been chosen. None of the test subjects showed injuries to the inner organs; however, numerous muscular hemorrhages as well as hemorrhages of discs and ligaments were noticed. The HIC values lay between 100 and 500; accelerations in x-direction up to 44g and in z-direction up to 85g occurred at the head. Lap-belt forces of 160 up to 400daN were measured. A weak point of the investigated system is that the child's movements are considerably limited, a factor also noticed in other child restraint systems; however, the protective function proved to be an advantage. The movements during the impact, pictured by high-speed cameras, essentially differ from those of adults wearing 3-point belts. The maximum flexion of the vertebral column is, due to the system, located in the transition of the thoracic to the lumbar vertebral column and the flexion angles amounted about 90°. As expected were the maximum head displacements in relation to a sled-fixed axis dependent on the impact velocity and the body height, and ranged between 50 cm (crash velocity 30 km/h, body height 97 cm) and 90 cm (crash velocity 40 km/h, body height 139 cm). The movements will be analysed; the anatomical and mechanical causes are going to be investigated. Finally will the results be compared with similar dummy tests investigated by us. Due to these differences in the dummy and cadaver behavior the necessity is pointed out to examine all restraint systems by cadaver tests.